GM_getValue is not defined (in injected code)?
code-injection, greasemonkey
Solution
That script is trying to run `GM_getValue()` from within the target-page scope (injected code); this is not allowed. If the code really must be injected, use the techniques from: How to use GM_xmlhttpRequest in Injected Code? or How to call Greasemonkey's GM_ functions from code that must run in the target page scope? to utilize `GM_` functions.
However, that script is using an obsolete and dangerous way to add jQuery. Don't do things like that. Worst-case, use this optimized, cross-platform method (second example). But, since you are on Greasemonkey (or Tampermonkey) that script can me made: much simpler, more secure, faster, and more efficient like so:
// ==UserScript==
// @name SO_test
// @include https://stackoverflow.com/*
// @version 1
// @require http://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js
// @grant GM_getValue
// @grant GM_setValue
// ==/UserScript==
$("#wmd-input").on ("contextmenu", function (e) {
e.preventDefault ();
//-- Important: note the comma and the correct case for `true`.
console.log ("GM_getValue: ", GM_getValue ("extra_markdown", true) );
});
Problem
I saw GM_getValue undefined error, however I did grant `GM_getValue` and `GM_setValue` and defined a default value. Example code: ``` // ==UserScript== // @name SO_test // @include https://stackoverflow.com/* // @version 1 // @grant GM_getValue // @grant GM_setValue // ==/UserScript== // Get jQuery thanks to this SO post: // https://stackoverflow.com/a/3550261/2730823 function addJQuery(callback) { var script = document.createElement("script"); script.setAttribute("src", "//ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"); script.addEventListener('load', function() { var script = document.createElement("script"); script.textContent = "window.jQ=jQuery.noConflict(true);(" + callback.toString() + ")();"; document.body.appendChild(script); }, false); document.body.appendChild(script); } function main() { $("#wmd-input").on("contextmenu", function(e) { e.preventDefault(); console.log("GM_getValue: " + GM_getValue("extra_markdown", True)); }); } addJQuery(main); ``` If you right click on the "add answer" textarea on SO after installing the above example, FF says `GM_getValue is undefined` in the console. Why is this? How do I get GM functions to work?